Renal colic is the passage of a renal calculus or kidney stone from the collecting structures of the kidney down the ureter. This is a very common and painful condition bringing patients for emergency medical treatment. The primary study that has been used primarily for diagnosis in the past is the pyelogram which involves administration of intravenous contrast agent and a series of abdominal films taken over several hours. Methods In this study, high-speed spiral CT was acquired in 34 patients presenting to the SUMC emergency room with possible renal colic. The CT data were acquired through the abdomen in about 45 seconds and subsequently reformatted using specialized software for which Dr. Napel has been our consultant. Using the CT technique, a high accuracy for diagnosing renal colic was achieved with superior sensitivity to diagnostic ultrasound which was used as the correlative study in this case. The work was presented at the Society of Uroradiology meeting in Palm Beach, Florida in January 1995 and won the first prize for best paper, in direct competition with scientific papers from other researchers in North America and Europe. Results and Discussion Future plans include application of the general techniques of CT scanning used in this study to the diagnosis of intrarenal calculi and renal tumors.